This study is designed to evaluate the effects of embryopathic agents on the induction of tissues and organs. An explant technique is employed as the experimental mode. Evaluation of teratogenesis is by gross anatomy of the developing organs, electron microscopy of the interacting cells and zone electrophoresis of isolated tissues before, during and after inductive interaction. the isoenzymes and families of enzymes evaluation are selected from a series of cellular metabolic pathways known to be altered concomitant with teratogenic sequences.